Testing device for electric lamps



April 7, 1953 D, Q KN|GHT 2,634,345

TESTING DEVICE FOR ELECTRIC LAMPS Filed MaI'Ch 3l, 1950 Patented Apr. 7,11953 UNITED .stares parleur ossi-CTE TESTNGDEVICE FOR ELECTRIC LMBS-.David ZC.'-Kniglut Newburyport, 'Mass ppiicatin' March 31, 1950,Srial No. 153,030

This'invention relates to improvements in electric lamp testing devicesLand more particularly to such devices which are Capable of testinglamps of both the one and two lament types as well as lamps having basescf different sizes. Lamp testing devices of the general variety to whichthe invention relates have a .particular utility in stores and shopswhere velectric lamps are sold 'and where it is desirable to *test eachYlamp at'the timecf purchase.

It is among the objects of my invention to provide a lamp testing deviceof the mentionedY general variety which may be manufactured andassembled at costs substantially below the costs to .manufacture andassembleithe prior comparable devices of which I am aware.

Another object is to provide a lamptesting device wherein eachlamp-receiving socket has a normally open switch therein -which must beclosed before a circuit'can be completed between contacts within thesocket, whereby any mere bridging of exposed/socket contacts by apersons nger or lingers cannot result in completion of a circuit withresulting -electric shock. According to the invention, one exposedcontact in each socket is a resilient switch contact which Imust beclosed before current can flow between socket contacts, and which isdicultly closable by a persons ngers,l especially while contact is beingmade'with` any other contact of the socket. It is, moreoverymy purposeand object generally toA improve the structure; utility and safetycharacteristics of electric "lamp testing devices and more especiallysuch devices having provision for testing both one and two filamentelec- Fig. 1 on a larger'scale; 'and Fig. 3 shows inper'spective 'theelectrical oonltact elements andc'onductors'in separated relation.

Fig'. `i is a 'bottom plarv'ew'of 'said device.

Referring to the drawing'the base I 0 maybe a V block of wood or of anyother suitable material having relatively good electrical insulatingprop- Ve1"cies ,'and may be of any desired shape. The i1- lustratedtwosocket lamp testeroonveniently Y may have a rectangular base l0through which two holes i2, 'I4 are drilled, or otherwise formed.

ffl-Idle "l2 is smaller in diameter than hole irland a'bushing' IE o'finsulatingrnateriaL'such asBake- -lite;'is"secure'd in h1e^|2`in anysuitable manner.

However, bushing I6 terminates substantially comms. (c1. zoo-5139)shallow notch '2E and projectingwithin the socket short ofextending.throughthetbase l0, isothat Sits .inner .end :provides ranAannu-lar.Av shoulder against which an insulating-icontact-carryingdiskf- I lmay be seated.

The ylarger'hole v'Ulfhas a similariinsulating bushing 2E? ysecured.thereingandl terminating substantially shcrtof `extending:through baseim, whereby it provides an.annular.shoulder at its inner end against.which .insulating ldiskq22c may 'oe seated.

Bushing i5 isdeeply gnotched'i'fatgd frornits inner endtowardits-imiterend,y and notchg24 is located at-that. portion v`of:bushing L6 which -is closest to bushingf. '.Dianietricaily:QIJDOSiteitsnotch 2Q, bushing,` Iii-has -.arelatively .shallow notch 26 at itsfinnerend.

Bushing 20 is similarly deeply notched at28 from its innerend towardits,outer.end,.and notch 28 is vlocated Aat that portion, of-bushingZUywhich is closest to bushingA 15,-wherebythe-notches'M. 2 3 of the two`busl'iingsareirialignment. Bushing y1.233 also has-a relativelyshallow.notch .3.0 vat its inner end diametrically oppositenotch 128.

Insulating disk .i 8 hasacentralrivetr; onthe like, extendingthrough it,with.the head of .the rivet constitutingga'centercontact Within lthesocket provided `by bushing'. '16. .Acontact-jelement 34 also is securedtodisk ."iby'therivet 32, it being secured toftheunderfsidefofVthediskland Vextending over the edgeoffthe disk witha'resilient Contactportionff34' ,extending withinv rthe in spaced relationltotheuppersurface Aof. disk '13, whereby it' can yieldresiliently within notch 28.toward the Vdisk i8. Aconductor-Bis electrical- 'ly' 'connected tovcontact.element 31d in any suitductor strip! is 'securdin'placefonbase l0 .with

" AonelegV attic rvextending'within''notch T24' 'ofv bushing le'andcwith'its :other leg T4011 extending with- Ain'notch 28Loi"bu'shing. ""LStripLQWmaybe-"secured to rbasetltini anysu,itable'"'Inann'er; as vby a tack 132 driven through"thebridgeioftheU-'strip strip tti.

vAccordingv to the invention,` fthe lega of' U strip 40 yconstitutesa;relatively'fixed contact 'fof a switch' twhicl 'has' aeresilientncontact A'element 46 exposed within the bushing I6 opposite the notch24 therein. Conveniently and economically, contact element 46 is clampedin operative relation to leg a by the insulating disk I8 when the latteris inserted to its seat. A strip of insulation 48 is arranged betweencontact element and leg 40a. at the lower vertically extending portionsthereof and, while these strips are held together in notch 24 by thelingers, the insulating disk I8 is forced to its seat with its edgeengaging the contact element 45 and clamping'it, insulation strip 48 andleg 40a together. The vertical portion of contact element 42 extendswithin notch 24 so that the walls of the notch maintain it in verticalposition, and the exposed contact portion 45' of element 46 isresiliently disposed within the bushing I6 in position to be engaged bythe screw shell contact of a lamp inserted in the bushing I6 of thetesting device, thereby to press the upper end portion of element 45into contact with leg 40a of conductor U-strip 4I). Meanwhile, thecenter contact of the lamp :will have engaged the center contact rivetof insulating disk I6 to close a circuit to the conductors 36, 44. Ifthe particular lamp being tested is a two-filament lamp, the usual ringcontact at the base of the lamp simultaneously will have engagedsocket'contact 34' to close a circuit for testing the second filament.

The insulating disk 22 has a centrally disposed rivet whosehead servesas the center contact for the socket formed by bushing 25, and has acontact element 52, similar to contact element 34 Vof disk I8. Contactelement 52 is secured by rivet 55 to the'under side of disk 22, andextends over the edge of the disk into bushing notch 30, with theresilient contact portion 52 disposed within the socket above disk 22.Conductor 44 leading from U-strip 40 extends out of base I5 andconstitutes one lead-in conductor of a conductor cord 54 whose otherlead-in conductor 55 set portion 55 of the terminal strip.

Before disk 22 is seated in base Il), a contact elementV 58 is arrangedin notch 28 of bushing 2li with a strip B of insulation interveningbetween the lower vertical portions of element 55 and leg 45h of U-strip45, following which the disk 22 is forced to its seat to securely holdthe contact element 58 in operative relation to leg `45h of U- strip4I). As in the earlier described case, thevleg Mib of U-strip 45constitutes a relatively xed contact of a switch whose resilient contact58 has the exposed contact portion 58' disposed within the socket inposition to be engaged and pressed into contact with leg 40h by thescrew shell contact of a lamp inserted in the socket. The center contactof the lamp will engage the center contact rivet 55, and the ringcontact of a two-filament lamp will simultaneously engage the contact52.

It will be apparent from the foregoing description that I have provideda lamp testing device which is economical to manufacture and assembleand which can effectively test diierent sizes of lamps of both the onelament and two filament types. But, of primary commercial importance,

, my testing device provides greater safety against Y. The provision ofa normally open switch in each socket which is readily closable by alamp inserted in a socket, but which is diiiicultly manually closable,constitutes a safety feature of major importance which is embodied in mytesting device with no increase in production costs as compared withprior lamp testing devices capable of performing the same tests.Actually, my disclosed structure enables the manufacture and assembly ofmy improved lamp testing devices at costs substantially below the coststo manufacture and assemble the prior' comparable testing devices ofwhich I am aware.

It is intended that the patent shall cover, by suitable expression inthe appended claims, whatever features of patentable novelty exist inthe invention disclosed.

I claim as my invention:

l. A lamp testing device comprising an insu lating base having across-seotionally circular hole therethrough, one end portion of saidhole having larger cross-section than the remainder of the hole wherebyan annular shoulder is provided at the plane of juncture of the largercross-section and smaller cross-section portions of the hole, the wallof said smaller cross-section portion of the hole having a groovetherein extending from `said shoulder to a mid-location along the axialextent of the smaller cross-section portion of said hole, a relativelyxed contact element secured in said groove and extending from saidgroove into the larger cross-section portion of saidV hole, aninsulating strip laid against the portion of lsaid contact element whichextends into said larger cross-section portion of said hole, a resilientcontact element laid against said insulating strip and extending intosaid groove in spaced relation to said relatively fixed contact elementtherein, an insulating disk pressed into said larger cross-sectionportion of said hole and seated against said annular shoulder, with Ytheedge of the disk clamping said contact elements and insulating striptogether,

Vsaid disk'having a center contact therein and saidY resilient contactelement having a contact portion disposed within the smallercross-section portion of said hole, and lead-in conductors connectedrespectively to said center contact on the disk'and said relativelyfixed contact element in said grooVe.,

K 2.7A lamp testing device having an insulating baseY with two axiallyparallel holes therethrough, eachsaid hole having a portion of reducedcross-section providing an annular shoullder at a mid-location along theextent of the vhole, said vportion of reduced cross-section of in thewallmof the other hole, a strip of insulation laid against each leg ofthe U-element, a resilient contact element laid againstk each saidstripvof insulation Yand extending into said grooves in spaced relationto the leg of the U- element in each groove, an insulating disk disposedacross each said hole and seated against the said annular shoulderthereof, with the edge of each said disk clamping a said resilientcontact element and a said insulating strip against one of the legs ofsaid U-element, a center contact on each said insulating disk, aseparate lead-in conductor connected to the center contact of each saidinsulating disk, and a second lead-in conductor connected to the said U-shaped conducting element.

3. A lamp testing device comprising a base made of insulating materialand having a circular hole extending therethrough, said hole havinggenerally uniform diameter throughout a major portion of its extent andhaving abruptly increased diameter at one end Whereby an annularshoulder is provided around the axis of the hole, said uniform diameterportion of the hole having a groove in its side Wall extending from saidshoulder, a xed contact at the bottom of said groove, a resilientcontact spaced and insulated from said xed contact and having aresilient portion disposed Within said hole and laterally yieldable intoengagement with said xed contact, an insulating disk seated against saidannular shoulder, a center contact on said disk, a resilient contact onsaid disk and yieldable toward the disk, said center contact, andresilient contacts being adapted to 6 be contacted by dilerent contactsof a lamp base inserted in said hole toward said disk, with saidresilient portion of the side Wall contact yielding into engagement withsaid xed contact, a lead-in conductor connected to said xed contact anda second 1ead-in conductor connected to both the center contact and theresilient contact on said insulating disk.

DAVID C. KNIGHT.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,689,485 Hendry Oct. 30, 19281,820,261 White Aug. 25, 1931 2,071,769 Schlicker et al. Feb. 23, 1937v2,158,851 Ceader May 16, 1939 2,191,336 Carroll Feb. 20, 1940 2,419,585OB'rien et al Apr. 29, 1947

